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Posted to commits@brooklyn.apache.org by al...@apache.org on 2015/08/12 17:55:38 UTC

[20/35] incubator-brooklyn git commit: [BROOKLYN-162] package rename to org.apache.brooklyn: software/webapp

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxControllerImpl.java
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diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxControllerImpl.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxControllerImpl.java
new file mode 100644
index 0000000..6b7a921
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxControllerImpl.java
@@ -0,0 +1,370 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import java.net.URI;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import org.apache.brooklyn.entity.proxy.AbstractControllerImpl;
+import org.apache.brooklyn.entity.proxy.ProxySslConfig;
+import org.apache.brooklyn.entity.proxy.nginx.NginxController.NginxControllerInternal;
+import org.apache.brooklyn.management.SubscriptionHandle;
+import org.apache.brooklyn.policy.PolicySpec;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import brooklyn.enricher.Enrichers;
+import brooklyn.entity.Entity;
+import brooklyn.entity.Group;
+import brooklyn.entity.annotation.Effector;
+import brooklyn.entity.basic.Attributes;
+import brooklyn.entity.basic.Lifecycle;
+import brooklyn.entity.basic.ServiceStateLogic.ServiceNotUpLogic;
+import brooklyn.entity.group.AbstractMembershipTrackingPolicy;
+import brooklyn.event.SensorEvent;
+import brooklyn.event.SensorEventListener;
+import brooklyn.event.feed.ConfigToAttributes;
+import brooklyn.event.feed.http.HttpFeed;
+import brooklyn.event.feed.http.HttpPollConfig;
+import brooklyn.event.feed.http.HttpValueFunctions;
+import brooklyn.util.ResourceUtils;
+import brooklyn.util.file.ArchiveUtils;
+import brooklyn.util.guava.Functionals;
+import brooklyn.util.http.HttpTool;
+import brooklyn.util.http.HttpToolResponse;
+import brooklyn.util.stream.Streams;
+import brooklyn.util.text.Strings;
+
+import com.google.common.base.Function;
+import com.google.common.base.Predicates;
+import com.google.common.base.Supplier;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Iterables;
+import com.google.common.collect.Sets;
+
+/**
+ * Implementation of the {@link NginxController} entity.
+ */
+public class NginxControllerImpl extends AbstractControllerImpl implements NginxController, NginxControllerInternal {
+
+    private static final Logger LOG = LoggerFactory.getLogger(NginxControllerImpl.class);
+
+    private volatile HttpFeed httpFeed;
+    private final Set<String> installedKeysCache = Sets.newLinkedHashSet();
+    protected UrlMappingsMemberTrackerPolicy urlMappingsMemberTrackerPolicy;
+    protected SubscriptionHandle targetAddressesHandler;
+
+    @Override
+    public void reload() {
+        NginxSshDriver driver = (NginxSshDriver)getDriver();
+        if (driver==null) {
+            Lifecycle state = getAttribute(NginxController.SERVICE_STATE_ACTUAL);
+            throw new IllegalStateException("Cannot reload (no driver instance; stopped? (state="+state+")");
+        }
+
+        driver.reload();
+    }
+
+    @Override
+    public boolean isSticky() {
+        return getConfig(STICKY);
+    }
+
+    private class UrlInferencer implements Supplier<URI> {
+        private Map<String, String> parameters;
+        private UrlInferencer(Map<String,String> parameters) {
+            this.parameters = parameters;
+        }
+        @Override public URI get() { 
+            String baseUrl = inferUrl(true);
+            if (parameters==null || parameters.isEmpty())
+                return URI.create(baseUrl);
+            return URI.create(baseUrl+"?"+HttpTool.encodeUrlParams(parameters));
+        }
+    }
+    
+    @Override
+    public void connectSensors() {
+        super.connectSensors();
+
+        ConfigToAttributes.apply(this);
+
+        // "up" is defined as returning a valid HTTP response from nginx (including a 404 etc)
+        httpFeed = addFeed(HttpFeed.builder()
+                .uniqueTag("nginx-poll")
+                .entity(this)
+                .period(getConfig(HTTP_POLL_PERIOD))
+                .baseUri(new UrlInferencer(null))
+                .poll(new HttpPollConfig<Boolean>(NGINX_URL_ANSWERS_NICELY)
+                        // Any response from Nginx is good.
+                        .checkSuccess(Predicates.alwaysTrue())
+                        // Accept any nginx response (don't assert specific version), so that sub-classing
+                        // for a custom nginx build is not strict about custom version numbers in headers
+                        .onResult(HttpValueFunctions.containsHeader("Server"))
+                        .setOnException(false)
+                        .suppressDuplicates(true))
+                .build());
+        
+        // TODO PERSISTENCE WORKAROUND kept anonymous function in case referenced in persisted state
+        new Function<HttpToolResponse, Boolean>() {
+            @Override
+            public Boolean apply(HttpToolResponse input) {
+                // Accept any nginx response (don't assert specific version), so that sub-classing
+                // for a custom nginx build is not strict about custom version numbers in headers
+                List<String> actual = input.getHeaderLists().get("Server");
+                return actual != null && actual.size() == 1;
+            }
+        };
+        
+        if (!Lifecycle.RUNNING.equals(getAttribute(SERVICE_STATE_ACTUAL))) {
+            // TODO when updating the map, if it would change from empty to empty on a successful run
+            // gate with the above check to prevent flashing on ON_FIRE during rebind (this is invoked on rebind as well as during start)
+            ServiceNotUpLogic.updateNotUpIndicator(this, NGINX_URL_ANSWERS_NICELY, "No response from nginx yet");
+        }
+        addEnricher(Enrichers.builder().updatingMap(Attributes.SERVICE_NOT_UP_INDICATORS)
+            .uniqueTag("not-up-unless-url-answers")
+            .from(NGINX_URL_ANSWERS_NICELY)
+            .computing(Functionals.ifNotEquals(true).value("URL where nginx listens is not answering correctly (with expected header)") )
+            .build());
+        connectServiceUpIsRunning();
+
+        // Can guarantee that parent/managementContext has been set
+        Group urlMappings = getConfig(URL_MAPPINGS);
+        if (urlMappings!=null && urlMappingsMemberTrackerPolicy==null) {
+            // Listen to the targets of each url-mapping changing
+            targetAddressesHandler = subscribeToMembers(urlMappings, UrlMapping.TARGET_ADDRESSES, new SensorEventListener<Collection<String>>() {
+                    @Override public void onEvent(SensorEvent<Collection<String>> event) {
+                        updateNeeded();
+                    }
+                });
+
+            // Listen to url-mappings being added and removed
+            urlMappingsMemberTrackerPolicy = addPolicy(PolicySpec.create(UrlMappingsMemberTrackerPolicy.class)
+                    .configure("group", urlMappings));
+        }
+    }
+
+    protected void removeUrlMappingsMemberTrackerPolicy() {
+        if (urlMappingsMemberTrackerPolicy != null) {
+            removePolicy(urlMappingsMemberTrackerPolicy);
+            urlMappingsMemberTrackerPolicy = null;
+        }
+        Group urlMappings = getConfig(URL_MAPPINGS);
+        if (urlMappings!=null && targetAddressesHandler!=null) {
+            unsubscribe(urlMappings, targetAddressesHandler);
+            targetAddressesHandler = null;
+        }
+    }
+    
+    public static class UrlMappingsMemberTrackerPolicy extends AbstractMembershipTrackingPolicy {
+        @Override
+        protected void onEntityEvent(EventType type, Entity entity) {
+            // relies on policy-rebind injecting the implementation rather than the dynamic-proxy
+            ((NginxControllerImpl)super.entity).updateNeeded();
+        }
+    }
+
+    @Override
+    protected void preStop() {
+        super.preStop();
+        removeUrlMappingsMemberTrackerPolicy();
+    }
+    
+    @Override
+    protected void postStop() {
+        // TODO don't want stop to race with the last poll.
+        super.postStop();
+        setAttribute(SERVICE_UP, false);
+    }
+
+    @Override
+    protected void disconnectSensors() {
+        if (httpFeed != null) httpFeed.stop();
+        disconnectServiceUpIsRunning();
+        super.disconnectSensors();
+    }
+
+    @Override
+    public Class<?> getDriverInterface() {
+        return NginxDriver.class;
+    }
+
+    @Override
+    public NginxDriver getDriver() {
+        return (NginxDriver) super.getDriver();
+    }
+
+    public void doExtraConfigurationDuringStart() {
+        computePortsAndUrls();
+        reconfigureService();
+        // reconnect sensors if ports have changed
+        connectSensors();
+    }
+
+    @Override
+    @Effector(description="Gets the current server configuration (by brooklyn recalculating what the config should be); does not affect the server")
+    public String getCurrentConfiguration() {
+        return getConfigFile();
+    }
+
+    @Override
+    @Effector(description="Deploys an archive of static content to the server")
+    public void deploy(String archiveUrl) {
+        NginxSshDriver driver = (NginxSshDriver) getDriver();
+        if (driver==null) {
+            if (LOG.isDebugEnabled())
+                LOG.debug("No driver for {}, so not deploying archive (is entity stopping? state={})",
+                        this, getAttribute(NginxController.SERVICE_STATE_ACTUAL));
+            return;
+        }
+
+        // Copy to the destination machine and extract contents
+        ArchiveUtils.deploy(archiveUrl, driver.getMachine(), driver.getRunDir());
+    }
+
+    @Override
+    public void reconfigureService() {
+        String cfg = getConfigFile();
+        if (cfg == null) return;
+
+        if (LOG.isDebugEnabled()) LOG.debug("Reconfiguring {}, targetting {} and {}", new Object[] {this, getServerPoolAddresses(), getUrlMappings()});
+        if (LOG.isTraceEnabled()) LOG.trace("Reconfiguring {}, config file:\n{}", this, cfg);
+
+        NginxSshDriver driver = (NginxSshDriver) getDriver();
+        if (!driver.isCustomizationCompleted()) {
+            if (LOG.isDebugEnabled()) LOG.debug("Reconfiguring {}, but driver's customization not yet complete so aborting", this);
+            return;
+        }
+
+        driver.getMachine().copyTo(Streams.newInputStreamWithContents(cfg), driver.getRunDir()+"/conf/server.conf");
+
+        installSslKeys("global", getSslConfig());
+
+        for (UrlMapping mapping : getUrlMappings()) {
+            //cache ensures only the first is installed, which is what is assumed below
+            installSslKeys(mapping.getDomain(), mapping.getConfig(UrlMapping.SSL_CONFIG));
+        }
+    }
+
+    /**
+     * Installs SSL keys named as {@code id.crt} and {@code id.key} where nginx can find them.
+     * <p>
+     * Currently skips re-installs (does not support changing)
+     */
+    public void installSslKeys(String id, ProxySslConfig ssl) {
+        if (ssl == null) return;
+
+        if (installedKeysCache.contains(id)) return;
+
+        NginxSshDriver driver = (NginxSshDriver) getDriver();
+
+        if (!Strings.isEmpty(ssl.getCertificateSourceUrl())) {
+            String certificateDestination = Strings.isEmpty(ssl.getCertificateDestination()) ? driver.getRunDir() + "/conf/" + id + ".crt" : ssl.getCertificateDestination();
+            driver.getMachine().copyTo(ImmutableMap.of("permissions", "0600"),
+                    ResourceUtils.create(this).getResourceFromUrl(ssl.getCertificateSourceUrl()),
+                    certificateDestination);
+        }
+
+        if (!Strings.isEmpty(ssl.getKeySourceUrl())) {
+            String keyDestination = Strings.isEmpty(ssl.getKeyDestination()) ? driver.getRunDir() + "/conf/" + id + ".key" : ssl.getKeyDestination();
+            driver.getMachine().copyTo(ImmutableMap.of("permissions", "0600"),
+                    ResourceUtils.create(this).getResourceFromUrl(ssl.getKeySourceUrl()),
+                    keyDestination);
+        }
+
+        installedKeysCache.add(id);
+    }
+
+    @Override
+    public String getConfigFile() {
+        NginxSshDriver driver = (NginxSshDriver) getDriver();
+        if (driver==null) {
+            LOG.debug("No driver for {}, so not generating config file (is entity stopping? state={})",
+                    this, getAttribute(NginxController.SERVICE_STATE_ACTUAL));
+            return null;
+        }
+
+        NginxConfigFileGenerator templateGenerator = getConfig(NginxController.SERVER_CONF_GENERATOR);
+        return templateGenerator.generateConfigFile(driver, this);
+    }
+
+    @Override
+    public Iterable<UrlMapping> getUrlMappings() {
+        // For mapping by URL
+        Group urlMappingGroup = getConfig(NginxController.URL_MAPPINGS);
+        if (urlMappingGroup != null) {
+            return Iterables.filter(urlMappingGroup.getMembers(), UrlMapping.class);
+        } else {
+            return Collections.<UrlMapping>emptyList();
+        }
+    }
+
+    @Override
+    public String getShortName() {
+        return "Nginx";
+    }
+
+    public boolean appendSslConfig(String id,
+            StringBuilder out,
+            String prefix,
+            ProxySslConfig ssl,
+            boolean sslBlock,
+            boolean certificateBlock) {
+        if (ssl == null)
+            return false;
+        if (sslBlock) {
+            out.append(prefix);
+            out.append("ssl on;\n");
+        }
+        if (ssl.getReuseSessions()) {
+            out.append(prefix);
+            out.append("proxy_ssl_session_reuse on;");
+        }
+        if (certificateBlock) {
+            String cert;
+            if (Strings.isEmpty(ssl.getCertificateDestination())) {
+                cert = "" + id + ".crt";
+            } else {
+                cert = ssl.getCertificateDestination();
+            }
+
+            out.append(prefix);
+            out.append("ssl_certificate " + cert + ";\n");
+
+            String key;
+            if (!Strings.isEmpty(ssl.getKeyDestination())) {
+                key = ssl.getKeyDestination();
+            } else if (!Strings.isEmpty(ssl.getKeySourceUrl())) {
+                key = "" + id + ".key";
+            } else {
+                key = null;
+            }
+
+            if (key != null) {
+                out.append(prefix);
+                out.append("ssl_certificate_key " + key + ";\n");
+            }
+        }
+        return true;
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDefaultConfigGenerator.java
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diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDefaultConfigGenerator.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDefaultConfigGenerator.java
new file mode 100644
index 0000000..dafa9cd
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDefaultConfigGenerator.java
@@ -0,0 +1,258 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import static java.lang.String.format;
+
+import java.util.Collection;
+
+import org.apache.brooklyn.entity.proxy.ProxySslConfig;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.google.common.collect.LinkedHashMultimap;
+import com.google.common.collect.Multimap;
+
+import brooklyn.util.text.Strings;
+
+/**
+ * Generates the {@code server.conf} configuration file using sensors on an {@link NginxController}.
+ */
+public class NginxDefaultConfigGenerator implements NginxConfigFileGenerator {
+
+    private static final Logger LOG = LoggerFactory.getLogger(NginxDefaultConfigGenerator.class);
+
+    public NginxDefaultConfigGenerator() { }
+
+    @Override
+    public String generateConfigFile(NginxDriver driver, NginxController nginx) {
+        StringBuilder config = new StringBuilder();
+        config.append("\n");
+        config.append(format("pid %s;\n", driver.getPidFile()));
+        config.append("events {\n");
+        config.append("  worker_connections 8196;\n");
+        config.append("}\n");
+        config.append("http {\n");
+
+        ProxySslConfig globalSslConfig = nginx.getSslConfig();
+
+        if (nginx.isSsl()) {
+            verifyConfig(globalSslConfig);
+            appendSslConfig("global", config, "    ", globalSslConfig, true, true);
+        }
+
+        // If no servers, then defaults to returning 404
+        // TODO Give nicer page back
+        if (nginx.getDomain()!=null || nginx.getServerPoolAddresses() == null || nginx.getServerPoolAddresses().isEmpty()) {
+            config.append("  server {\n");
+            config.append(getCodeForServerConfig());
+            config.append("    listen "+nginx.getPort()+";\n");
+            config.append(getCodeFor404());
+            config.append("  }\n");
+        }
+
+        // For basic round-robin across the server-pool
+        if (nginx.getServerPoolAddresses() != null && nginx.getServerPoolAddresses().size() > 0) {
+            config.append(format("  upstream "+nginx.getId()+" {\n"));
+            if (nginx.isSticky()){
+                config.append("    sticky;\n");
+            }
+            for (String address : nginx.getServerPoolAddresses()) {
+                config.append("    server "+address+";\n");
+            }
+            config.append("  }\n");
+            config.append("  server {\n");
+            config.append(getCodeForServerConfig());
+            config.append("    listen "+nginx.getPort()+";\n");
+            if (nginx.getDomain()!=null)
+                config.append("    server_name "+nginx.getDomain()+";\n");
+            config.append("    location / {\n");
+            config.append("      proxy_pass "+(globalSslConfig != null && globalSslConfig.getTargetIsSsl() ? "https" : "http")+"://"+nginx.getId()+";\n");
+            config.append("    }\n");
+            config.append("  }\n");
+        }
+
+        // For mapping by URL
+        Iterable<UrlMapping> mappings = nginx.getUrlMappings();
+        Multimap<String, UrlMapping> mappingsByDomain = LinkedHashMultimap.create();
+        for (UrlMapping mapping : mappings) {
+            Collection<String> addrs = mapping.getAttribute(UrlMapping.TARGET_ADDRESSES);
+            if (addrs != null && addrs.size() > 0) {
+                mappingsByDomain.put(mapping.getDomain(), mapping);
+            }
+        }
+
+        for (UrlMapping um : mappings) {
+            Collection<String> addrs = um.getAttribute(UrlMapping.TARGET_ADDRESSES);
+            if (addrs != null && addrs.size() > 0) {
+                config.append(format("  upstream "+um.getUniqueLabel()+" {\n"));
+                if (nginx.isSticky()){
+                    config.append("    sticky;\n");
+                }
+                for (String address: addrs) {
+                    config.append("    server "+address+";\n");
+                }
+                config.append("  }\n");
+            }
+        }
+
+        for (String domain : mappingsByDomain.keySet()) {
+            config.append("  server {\n");
+            config.append(getCodeForServerConfig());
+            config.append("    listen "+nginx.getPort()+";\n");
+            config.append("    server_name "+domain+";\n");
+            boolean hasRoot = false;
+
+            // set up SSL
+            ProxySslConfig localSslConfig = null;
+            for (UrlMapping mappingInDomain : mappingsByDomain.get(domain)) {
+                ProxySslConfig sslConfig = mappingInDomain.getConfig(UrlMapping.SSL_CONFIG);
+                if (sslConfig!=null) {
+                    verifyConfig(sslConfig);
+                    if (localSslConfig!=null) {
+                        if (localSslConfig.equals(sslConfig)) {
+                            //ignore identical config specified on multiple mappings
+                        } else {
+                            LOG.warn("{} mapping {} provides SSL config for {} when a different config had already been provided by another mapping, ignoring this one",
+                                    new Object[] {this, mappingInDomain, domain});
+                        }
+                    } else if (globalSslConfig!=null) {
+                        if (globalSslConfig.equals(sslConfig)) {
+                            //ignore identical config specified on multiple mappings
+                        } else {
+                            LOG.warn("{} mapping {} provides SSL config for {} when a different config had been provided at root nginx scope, ignoring this one",
+                                    new Object[] {this, mappingInDomain, domain});
+                        }
+                    } else {
+                        //new config, is okay
+                        localSslConfig = sslConfig;
+                    }
+                }
+            }
+            if (localSslConfig != null) {
+                appendSslConfig(domain, config, "    ", localSslConfig, true, true);
+            }
+
+            for (UrlMapping mappingInDomain : mappingsByDomain.get(domain)) {
+                // TODO Currently only supports "~" for regex. Could add support for other options,
+                // such as "~*", "^~", literals, etc.
+                boolean isRoot = mappingInDomain.getPath()==null || mappingInDomain.getPath().length()==0 || mappingInDomain.getPath().equals("/");
+                if (isRoot && hasRoot) {
+                    LOG.warn(""+this+" mapping "+mappingInDomain+" provides a duplicate / proxy, ignoring");
+                } else {
+                    hasRoot |= isRoot;
+                    String location = isRoot ? "/" : "~ " + mappingInDomain.getPath();
+                    config.append("    location "+location+" {\n");
+                    Collection<UrlRewriteRule> rewrites = mappingInDomain.getConfig(UrlMapping.REWRITES);
+                    if (rewrites != null && rewrites.size() > 0) {
+                        for (UrlRewriteRule rule: rewrites) {
+                            config.append("      rewrite \"^"+rule.getFrom()+"$\" \""+rule.getTo()+"\"");
+                            if (rule.isBreak()) config.append(" break");
+                            config.append(" ;\n");
+                        }
+                    }
+                    config.append("      proxy_pass "+
+                        (localSslConfig != null && localSslConfig.getTargetIsSsl() ? "https" :
+                         (localSslConfig == null && globalSslConfig != null && globalSslConfig.getTargetIsSsl()) ? "https" :
+                         "http")+
+                        "://"+mappingInDomain.getUniqueLabel()+" ;\n");
+                    config.append("    }\n");
+                }
+            }
+            if (!hasRoot) {
+                //provide a root block giving 404 if there isn't one for this server
+                config.append("    location / { \n"+getCodeFor404()+"    }\n");
+            }
+            config.append("  }\n");
+        }
+
+        config.append("}\n");
+
+        return config.toString();
+    }
+
+    protected String getCodeForServerConfig() {
+        // See http://wiki.nginx.org/HttpProxyModule
+        return ""+
+            // this prevents nginx from reporting version number on error pages
+            "    server_tokens off;\n"+
+
+            // this prevents nginx from using the internal proxy_pass codename as Host header passed upstream.
+            // Not using $host, as that causes integration test to fail with a "connection refused" testing
+            // url-mappings, at URL "http://localhost:${port}/atC0" (with a trailing slash it does work).
+            "    proxy_set_header Host $http_host;\n"+
+
+            // following added, as recommended for wordpress in:
+            // http://zeroturnaround.com/labs/wordpress-protips-go-with-a-clustered-approach/#!/
+            "    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;\n"+
+            "    proxy_set_header X-Real-IP $remote_addr;\n";
+    }
+
+    protected String getCodeFor404() {
+        return "    return 404;\n";
+    }
+
+    protected void verifyConfig(ProxySslConfig proxySslConfig) {
+          if(Strings.isEmpty(proxySslConfig.getCertificateDestination()) && Strings.isEmpty(proxySslConfig.getCertificateSourceUrl())){
+            throw new IllegalStateException("ProxySslConfig can't have a null certificateDestination and null certificateSourceUrl. One or both need to be set");
+        }
+    }
+
+    protected boolean appendSslConfig(String id, StringBuilder out, String prefix, ProxySslConfig ssl,
+                                   boolean sslBlock, boolean certificateBlock) {
+        if (ssl == null) return false;
+        if (sslBlock) {
+            out.append(prefix);
+            out.append("ssl on;\n");
+        }
+        if (ssl.getReuseSessions()) {
+            out.append(prefix);
+            out.append("");
+        }
+        if (certificateBlock) {
+            String cert;
+            if (Strings.isEmpty(ssl.getCertificateDestination())) {
+                cert = "" + id + ".crt";
+            } else {
+                cert = ssl.getCertificateDestination();
+            }
+
+            out.append(prefix);
+            out.append("ssl_certificate " + cert + ";\n");
+
+            String key;
+            if (!Strings.isEmpty(ssl.getKeyDestination())) {
+                key = ssl.getKeyDestination();
+            } else if (!Strings.isEmpty(ssl.getKeySourceUrl())) {
+                key = "" + id + ".key";
+            } else {
+                key = null;
+            }
+
+            if (key != null) {
+                out.append(prefix);
+                out.append("ssl_certificate_key " + key + ";\n");
+            }
+
+            out.append("ssl_protocols TLSv1 TLSv1.1 TLSv1.2;\n");
+        }
+        return true;
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDriver.java
----------------------------------------------------------------------
diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDriver.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDriver.java
new file mode 100644
index 0000000..48a0534
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxDriver.java
@@ -0,0 +1,31 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import brooklyn.entity.basic.SoftwareProcessDriver;
+
+public interface NginxDriver extends SoftwareProcessDriver {
+
+    String getRunDir();
+
+    String getPidFile();
+
+    boolean isCustomizationCompleted();
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxSshDriver.java
----------------------------------------------------------------------
diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxSshDriver.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxSshDriver.java
new file mode 100644
index 0000000..27ab94c
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxSshDriver.java
@@ -0,0 +1,477 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import static java.lang.String.format;
+
+import java.util.List;
+import java.util.concurrent.atomic.AtomicLong;
+
+import org.apache.brooklyn.entity.proxy.AbstractController;
+import org.apache.brooklyn.management.ManagementContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import brooklyn.entity.basic.AbstractSoftwareProcessSshDriver;
+import brooklyn.entity.basic.Attributes;
+import brooklyn.entity.basic.Entities;
+import brooklyn.entity.basic.EntityInternal;
+import brooklyn.entity.basic.Lifecycle;
+import brooklyn.entity.basic.lifecycle.ScriptHelper;
+import brooklyn.entity.drivers.downloads.DownloadResolver;
+import brooklyn.location.OsDetails;
+import brooklyn.location.basic.SshMachineLocation;
+import brooklyn.util.collections.MutableMap;
+import brooklyn.util.exceptions.Exceptions;
+import brooklyn.util.net.Networking;
+import brooklyn.util.os.Os;
+import brooklyn.util.ssh.BashCommands;
+import brooklyn.util.stream.Streams;
+import brooklyn.util.task.DynamicTasks;
+import brooklyn.util.task.Tasks;
+import brooklyn.util.task.ssh.SshTasks;
+import brooklyn.util.task.ssh.SshTasks.OnFailingTask;
+import brooklyn.util.text.Strings;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+
+/**
+ * Start a {@link NginxController} in a {@link brooklyn.location.Location} accessible over ssh.
+ */
+public class NginxSshDriver extends AbstractSoftwareProcessSshDriver implements NginxDriver {
+
+    // TODO An alternative way of installing nginx is described at:
+    //   http://sjp.co.nz/posts/building-nginx-for-debian-systems/
+    // It's use of `apt-get source nginx` and `apt-get build-dep nginx` makes
+    // it look higher level and therefore more appealing.
+
+    public static final Logger log = LoggerFactory.getLogger(NginxSshDriver.class);
+    public static final String NGINX_PID_FILE = "logs/nginx.pid";
+
+    private boolean customizationCompleted = false;
+
+    public NginxSshDriver(NginxControllerImpl entity, SshMachineLocation machine) {
+        super(entity, machine);
+
+        entity.setAttribute(Attributes.LOG_FILE_LOCATION, getLogFileLocation());
+        entity.setAttribute(NginxController.ACCESS_LOG_LOCATION, getAccessLogLocation());
+        entity.setAttribute(NginxController.ERROR_LOG_LOCATION, getErrorLogLocation());
+    }
+
+    @Override
+    public NginxControllerImpl getEntity() {
+        return (NginxControllerImpl) super.getEntity();
+    }
+
+    public String getLogFileLocation() {
+        return format("%s/console", getRunDir());
+    }
+
+    public String getAccessLogLocation() {
+        String accessLog = entity.getConfig(NginxController.ACCESS_LOG_LOCATION);
+        return format("%s/%s", getRunDir(), accessLog);
+    }
+
+    public String getErrorLogLocation() {
+        String errorLog = entity.getConfig(NginxController.ERROR_LOG_LOCATION);
+        return format("%s/%s", getRunDir(), errorLog);
+    }
+
+    /** By default Nginx writes the pid of the master process to {@code logs/nginx.pid} */
+    @Override
+    public String getPidFile() {
+        return format("%s/%s", getRunDir(), NGINX_PID_FILE);
+    }
+
+    @Deprecated /** @deprecated since 0.7.0 use #getPort */
+    public Integer getHttpPort() {
+        return getEntity().getPort();
+    }
+
+    public Integer getPort() {
+        return getEntity().getPort();
+    }
+
+    @Override
+    public void rebind() {
+        customizationCompleted = true;
+    }
+
+    @Override
+    public void postLaunch() {
+        entity.setAttribute(NginxController.PID_FILE, getRunDir() + "/" + AbstractSoftwareProcessSshDriver.PID_FILENAME);
+        if (((AbstractController)entity).isSsl()) {
+            entity.setAttribute(Attributes.HTTPS_PORT, getPort());
+            ((EntityInternal)entity).removeAttribute(Attributes.HTTP_PORT);
+        } else {
+            entity.setAttribute(Attributes.HTTP_PORT, getPort());
+            ((EntityInternal)entity).removeAttribute(Attributes.HTTPS_PORT);
+        }
+        super.postLaunch();
+    }
+
+    @Override
+    public void preInstall() {
+        resolver = Entities.newDownloader(this);
+        setExpandedInstallDir(Os.mergePaths(getInstallDir(), resolver.getUnpackedDirectoryName(format("nginx-%s", getVersion()))));
+    }
+
+    @Override
+    public void install() {
+        // inessential here, installation will fail later if it needs to sudo (eg if using port 80)
+        DynamicTasks.queueIfPossible(SshTasks.dontRequireTtyForSudo(getMachine(), OnFailingTask.WARN_OR_IF_DYNAMIC_FAIL_MARKING_INESSENTIAL)).orSubmitAndBlock();
+
+        List<String> nginxUrls = resolver.getTargets();
+        String nginxSaveAs = resolver.getFilename();
+
+        boolean sticky = ((NginxController) entity).isSticky();
+        boolean isMac = getMachine().getOsDetails().isMac();
+
+        MutableMap<String, String> installGccPackageFlags = MutableMap.of(
+                "onlyifmissing", "gcc",
+                "yum", "gcc",
+                "apt", "gcc",
+                "zypper", "gcc",
+                "port", null);
+        MutableMap<String, String> installMakePackageFlags = MutableMap.of(
+                "onlyifmissing", "make",
+                "yum", "make",
+                "apt", "make",
+                "zypper", "make",
+                "port", null);
+        MutableMap<String, String> installPackageFlags = MutableMap.of(
+                "yum", "openssl-devel pcre-devel",
+                "apt", "libssl-dev zlib1g-dev libpcre3-dev",
+                "zypper", "libopenssl-devel pcre-devel",
+                "port", null);
+
+        String stickyModuleVersion = entity.getConfig(NginxController.STICKY_VERSION);
+        DownloadResolver stickyModuleResolver = mgmt().getEntityDownloadsManager().newDownloader(
+                this, "stickymodule", ImmutableMap.of("addonversion", stickyModuleVersion));
+        List<String> stickyModuleUrls = stickyModuleResolver.getTargets();
+        String stickyModuleSaveAs = stickyModuleResolver.getFilename();
+        String stickyModuleExpandedInstallDir = String.format("%s/src/%s", getExpandedInstallDir(),
+                stickyModuleResolver.getUnpackedDirectoryName("nginx-sticky-module-"+stickyModuleVersion));
+
+        List<String> cmds = Lists.newArrayList();
+
+        cmds.add(BashCommands.INSTALL_TAR);
+        cmds.add(BashCommands.alternatives(
+                BashCommands.ifExecutableElse0("apt-get", BashCommands.installPackage("build-essential")),
+                BashCommands.ifExecutableElse0("yum", BashCommands.sudo("yum -y --nogpgcheck groupinstall \"Development Tools\""))));
+        cmds.add(BashCommands.installPackage(installGccPackageFlags, "nginx-prerequisites-gcc"));
+        cmds.add(BashCommands.installPackage(installMakePackageFlags, "nginx-prerequisites-make"));
+        cmds.add(BashCommands.installPackage(installPackageFlags, "nginx-prerequisites"));
+        cmds.addAll(BashCommands.commandsToDownloadUrlsAs(nginxUrls, nginxSaveAs));
+
+        String pcreExpandedInstallDirname = "";
+        if (isMac) {
+            String pcreVersion = entity.getConfig(NginxController.PCRE_VERSION);
+            DownloadResolver pcreResolver = mgmt().getEntityDownloadsManager().newDownloader(
+                    this, "pcre", ImmutableMap.of("addonversion", pcreVersion));
+            List<String> pcreUrls = pcreResolver.getTargets();
+            String pcreSaveAs = pcreResolver.getFilename();
+            pcreExpandedInstallDirname = pcreResolver.getUnpackedDirectoryName("pcre-"+pcreVersion);
+
+            // Install PCRE
+            cmds.addAll(BashCommands.commandsToDownloadUrlsAs(pcreUrls, pcreSaveAs));
+            cmds.add(format("mkdir -p %s/pcre-dist", getInstallDir()));
+            cmds.add(format("tar xvzf %s", pcreSaveAs));
+            cmds.add(format("cd %s", pcreExpandedInstallDirname));
+            cmds.add(format("./configure --prefix=%s/pcre-dist", getInstallDir()));
+            cmds.add("make");
+            cmds.add("make install");
+            cmds.add("cd ..");
+        }
+
+        cmds.add(format("tar xvzf %s", nginxSaveAs));
+        cmds.add(format("cd %s", getExpandedInstallDir()));
+
+        if (sticky) {
+            // Latest versions of sticky module expand to a different folder than the file name.
+            // Extract to folder set by us so we know where the sources are.
+            cmds.add(format("mkdir -p %s", stickyModuleExpandedInstallDir));
+            cmds.add(format("pushd %s", stickyModuleExpandedInstallDir));
+            cmds.addAll(BashCommands.commandsToDownloadUrlsAs(stickyModuleUrls, stickyModuleSaveAs));
+            cmds.add(format("tar --strip-component=1 -xvzf %s", stickyModuleSaveAs));
+            cmds.add("popd");
+        }
+
+        // Note that for OS X, not including space after "-L" because broken in 10.6.8 (but fixed in 10.7.x)
+        //      see http://trac.nginx.org/nginx/ticket/227
+        String withLdOpt = entity.getConfig(NginxController.WITH_LD_OPT);
+        if (isMac) withLdOpt = format("-L%s/pcre-dist/lib", getInstallDir()) + (Strings.isBlank(withLdOpt) ? "" : " " + withLdOpt);
+        String withCcOpt = entity.getConfig(NginxController.WITH_CC_OPT);
+        
+        if (isMac) {
+            // TODO Upgrade sticky module as soon as a fix for https://bitbucket.org/nginx-goodies/nginx-sticky-module-ng/issue/16/can-not-compile-on-macosx-yosemite
+            // is released and remove this block.
+            withCcOpt = (Strings.isBlank(withCcOpt) ? "" : (withCcOpt + " ")) + "-Wno-error";
+        }
+
+        StringBuilder configureCommand = new StringBuilder("./configure")
+                .append(format(" --prefix=%s/dist", getExpandedInstallDir()))
+                .append(" --with-http_ssl_module")
+                .append(sticky ? format(" --add-module=%s ", stickyModuleExpandedInstallDir) : "")
+                .append(!Strings.isBlank(withLdOpt) ? format(" --with-ld-opt=\"%s\"", withLdOpt) : "")
+                .append(!Strings.isBlank(withCcOpt) ? format(" --with-cc-opt=\"%s\"", withCcOpt) : "")
+                ;
+        if (isMac) {
+            configureCommand.append(" --with-pcre=")
+                    .append(getInstallDir()).append("/").append(pcreExpandedInstallDirname);
+        }
+
+        cmds.addAll(ImmutableList.of(
+                "mkdir -p dist",
+                configureCommand.toString(),
+                "make install"));
+
+        ScriptHelper script = newScript(INSTALLING)
+                .body.append(cmds)
+                .header.prepend("set -x")
+                .gatherOutput()
+                .failOnNonZeroResultCode(false);
+
+        int result = script.execute();
+
+        if (result != 0) {
+            String notes = "likely an error building nginx. consult the brooklyn log ssh output for further details.\n"+
+                    "note that this Brooklyn nginx driver compiles nginx from source. " +
+                    "it attempts to install common prerequisites but this does not always succeed.\n";
+            OsDetails os = getMachine().getOsDetails();
+            if (os.isMac()) {
+                notes += "deploying to Mac OS X, you will require Xcode and Xcode command-line tools, and on " +
+                        "some versions the pcre library (e.g. using macports, sudo port install pcre).\n";
+            }
+            if (os.isWindows()) {
+                notes += "this nginx driver is not designed for windows, unless cygwin is installed, and you are patient.\n";
+            }
+            if (getEntity().getApplication().getClass().getCanonicalName().startsWith("brooklyn.demo.")) {
+                // this is maybe naughty ... but since we use nginx in the first demo example,
+                // and since it's actually pretty complicated, let's give a little extra hand-holding
+                notes +=
+                        "if debugging this is all a bit much and you just want to run a demo, " +
+                        "you have two fairly friendly options.\n" +
+                        "1. you can use a well known cloud, like AWS or Rackspace, where this should run " +
+                        "in a tried-and-tested Ubuntu or CentOS environment, without any problems " +
+                        "(and if it does let us know and we'll fix it!).\n"+
+                        "2. or you can just use the demo without nginx, instead access the appserver instances directly.\n";
+            }
+
+            if (!script.getResultStderr().isEmpty()) {
+                notes += "\n" + "STDERR\n" + script.getResultStderr()+"\n";
+                Streams.logStreamTail(log, "STDERR of problem in "+Tasks.current(), Streams.byteArrayOfString(script.getResultStderr()), 1024);
+            }
+            if (!script.getResultStdout().isEmpty()) {
+                notes += "\n" + "STDOUT\n" + script.getResultStdout()+"\n";
+                Streams.logStreamTail(log, "STDOUT of problem in "+Tasks.current(), Streams.byteArrayOfString(script.getResultStdout()), 1024);
+            }
+
+            Tasks.setExtraStatusDetails(notes.trim());
+
+            throw new IllegalStateException("Installation of nginx failed (shell returned non-zero result "+result+")");
+        }
+    }
+
+    private ManagementContext mgmt() {
+        return ((EntityInternal) entity).getManagementContext();
+    }
+
+    @Override
+    public void customize() {
+        newScript(CUSTOMIZING)
+                .body.append(
+                        format("mkdir -p %s", getRunDir()),
+                        format("cp -R %s/dist/{conf,html,logs,sbin} %s", getExpandedInstallDir(), getRunDir()))
+                .execute();
+
+        // Install static content archive, if specified
+        String archiveUrl = entity.getConfig(NginxController.STATIC_CONTENT_ARCHIVE_URL);
+        if (Strings.isNonBlank(archiveUrl)) {
+            getEntity().deploy(archiveUrl);
+        }
+
+        customizationCompleted = true;
+    }
+
+    @Override
+    public boolean isCustomizationCompleted() {
+        return customizationCompleted;
+    }
+
+    @Override
+    public void launch() {
+        // TODO if can't be root, and ports > 1024 are in the allowed port range,
+        // prefer that; could do this on SshMachineLocation which implements PortSupplier,
+        // invoked from PortAttrSensorAndConfigKey, which is invoked from MachineLifecycleTasks.preStartCustom
+        Networking.checkPortsValid(MutableMap.of("port", getPort()));
+
+        getEntity().doExtraConfigurationDuringStart();
+
+        // We wait for evidence of running because, using
+        // brooklyn.ssh.config.tool.class=brooklyn.util.internal.ssh.cli.SshCliTool,
+        // we saw the ssh session return before the tomcat process was fully running
+        // so the process failed to start.
+        newScript(MutableMap.of("usePidFile", false), LAUNCHING)
+                .body.append(
+                        format("cd %s", getRunDir()),
+                        BashCommands.requireExecutable("./sbin/nginx"),
+                        sudoBashCIfPrivilegedPort(getPort(), format(
+                                "nohup ./sbin/nginx -p %s/ -c conf/server.conf > %s 2>&1 &", getRunDir(), getLogFileLocation())),
+                        format("for i in {1..10}\n" +
+                                "do\n" +
+                                "    test -f %1$s && ps -p `cat %1$s` && exit\n" +
+                                "    sleep 1\n" +
+                                "done\n" +
+                                "echo \"No explicit error launching nginx but couldn't find process by pid; continuing but may subsequently fail\"\n" +
+                                "cat %2$s | tee /dev/stderr",
+                                getPidFile(), getLogFileLocation()))
+                .execute();
+    }
+
+    public static String sudoIfPrivilegedPort(int port, String command) {
+        return port < 1024 ? BashCommands.sudo(command) : command;
+    }
+
+    public static String sudoBashCIfPrivilegedPort(int port, String command) {
+        return port < 1024 ? BashCommands.sudo("bash -c '"+command+"'") : command;
+    }
+
+    @Override
+    public boolean isRunning() {
+        return newScript(MutableMap.of("usePidFile", getPidFile()), CHECK_RUNNING).execute() == 0;
+    }
+
+    @Override
+    public void stop() {
+        // Don't `kill -9`, as that doesn't stop the worker processes
+        newScript(MutableMap.of("usePidFile", false), STOPPING).
+                body.append(
+                        format("cd %s", getRunDir()),
+                        format("export PID=`cat %s`", getPidFile()),
+                        "test -n \"$PID\" || exit 0",
+                        sudoIfPrivilegedPort(getPort(), "kill $PID"))
+                .execute();
+    }
+
+    @Override
+    public void kill() {
+        stop();
+    }
+
+    private final ExecController reloadExecutor = new ExecController(
+            entity+"->reload",
+            new Runnable() {
+                @Override
+                public void run() {
+                    reloadImpl();
+                }
+            });
+
+    public void reload() {
+        // If there are concurrent calls to reload (such that some calls come in when another call is queued), then
+        // don't bother doing the subsequent calls. Instead just rely on the currently queued call.
+        //
+        // Motivation is that calls to nginx.reload were backing up: we ended up executing lots of them in parallel
+        // when there were several changes to the nginx conifg that requiring a reload. The problem can be particularly
+        // bad because the ssh commands take a second or two - if 10 changes were made to the config in that time, we'd
+        // end up executing reload 10 times in parallel.
+
+        reloadExecutor.run();
+    }
+
+    private void reloadImpl() {
+        // Note that previously, if serviceUp==false then we'd restart nginx.
+        // That caused a race on stop()+reload(): nginx could simultaneously be stopping and also reconfiguring
+        // (e.g. due to a cluster-resize), the restart() would leave nginx running even after stop() had returned.
+        //
+        // Now we rely on NginxController always calling update (and thus reload) once it has started. This is
+        // done in AbstractController.postActivation().
+        //
+        // If our blocking check sees that !isRunning() (and if a separate thread is starting it, and subsequently
+        // calling waitForEntityStart()), we can guarantee that the start-thread's call to update will happen after
+        // this call to reload. So we this can be a no-op, and just rely on that subsequent call to update.
+
+        Lifecycle lifecycle = entity.getAttribute(NginxController.SERVICE_STATE_ACTUAL);
+        if (lifecycle==Lifecycle.STOPPING || lifecycle==Lifecycle.STOPPED || !isRunning()) {
+            log.debug("Ignoring reload of nginx "+entity+", because service is not running (state "+lifecycle+")");
+            return;
+        }
+
+        doReloadNow();
+    }
+
+    /**
+     * Instructs nginx to reload its configuration (without restarting, so don't lose any requests).
+     * Can be overridden if necessary, to change the call used for reloading.
+     */
+    private void doReloadNow() {
+        // We use kill -HUP because that is recommended at http://wiki.nginx.org/CommandLine,
+        // but there is no noticeable difference (i.e. no impact on #365) compared to:
+        //   sudoIfPrivilegedPort(getHttpPort(), format("./sbin/nginx -p %s/ -c conf/server.conf -s reload", getRunDir()))
+        //
+        // Note that if conf file is invalid, you'll get no stdout/stderr from `kill` but you
+        // do from using `nginx ... -s reload` so that can be handy when manually debugging.
+
+        log.debug("reloading nginx by simularing restart (kill -HUP) - {}", entity);
+        newScript(RESTARTING)
+                .body.append(
+                        format("cd %s", getRunDir()),
+                        format("export PID=`cat %s`", getPidFile()),
+                        sudoIfPrivilegedPort(getPort(), "kill -HUP $PID"))
+                .execute();
+    }
+
+    /**
+     * Executes the given task, but only if another thread hasn't executed it for us (where the other thread
+     * began executing it after the current caller of {@link #run()} began attempting to do so itself).
+     *
+     * @author aled
+     */
+    private static class ExecController {
+        private final String summary;
+        private final Runnable task;
+        private final AtomicLong counter = new AtomicLong();
+
+        ExecController(String summary, Runnable task) {
+            this.summary = summary;
+            this.task = task;
+        }
+
+        void run() {
+            long preCount = counter.get();
+            synchronized (this) {
+                if (counter.compareAndSet(preCount, preCount+1)) {
+                    try {
+                        if (log.isDebugEnabled()) log.debug("Executing {}; incremented count to {}", new Object[] {summary, counter});
+                        task.run();
+                    } catch (Exception e) {
+                        if (log.isDebugEnabled()) log.debug("Failed executing {}; reseting count to {} and propagating exception: {}", new Object[] {summary, preCount, e});
+                        counter.set(preCount);
+                        throw Exceptions.propagate(e);
+                    }
+                } else {
+                    if (log.isDebugEnabled()) log.debug("Not executing {} because executed by another thread subsequent to us attempting (preCount {}; count {})", new Object[] {summary, preCount, counter});
+                }
+            }
+        }
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxTemplateConfigGenerator.java
----------------------------------------------------------------------
diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxTemplateConfigGenerator.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxTemplateConfigGenerator.java
new file mode 100644
index 0000000..34432dd7
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/NginxTemplateConfigGenerator.java
@@ -0,0 +1,83 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import java.util.Collection;
+import java.util.Map;
+
+import org.apache.brooklyn.entity.proxy.ProxySslConfig;
+
+import brooklyn.config.ConfigKey;
+import brooklyn.entity.basic.ConfigKeys;
+import brooklyn.util.ResourceUtils;
+import brooklyn.util.collections.MutableMap;
+import brooklyn.util.text.Strings;
+import brooklyn.util.text.TemplateProcessor;
+
+import com.google.common.collect.LinkedHashMultimap;
+import com.google.common.collect.Multimap;
+
+/**
+ * Processes a FreeMarker template to generate the {@code server.conf} configuration file for an 
+ * {@link NginxController}.
+ * <p>
+ * Note this must be explicitly enabled via {@link NginxController#SERVER_CONF_GENERATOR}.
+ */
+public class NginxTemplateConfigGenerator implements NginxConfigFileGenerator {
+
+    public static final ConfigKey<String> SERVER_CONF_TEMPLATE_URL = ConfigKeys.newStringConfigKey(
+            "nginx.config.templateUrl", "The server.conf configuration file URL (FreeMarker template). "
+                + "Only applies if 'nginx.config.generator' specifies a generator which uses a template.", 
+                "classpath://org/apache/brooklyn/entity/proxy/nginx/server.conf");
+
+    public NginxTemplateConfigGenerator() { }
+
+    @Override
+    public String generateConfigFile(NginxDriver driver, NginxController nginx) {
+        // Check template URL exists
+        String templateUrl = driver.getEntity().getConfig(NginxController.SERVER_CONF_TEMPLATE_URL);
+        ResourceUtils.create(this).checkUrlExists(templateUrl);
+
+        // Check SSL configuration
+        ProxySslConfig ssl = driver.getEntity().getConfig(NginxController.SSL_CONFIG);
+        if (ssl != null && Strings.isEmpty(ssl.getCertificateDestination()) && Strings.isEmpty(ssl.getCertificateSourceUrl())) {
+            throw new IllegalStateException("ProxySslConfig can't have a null certificateDestination and null certificateSourceUrl. One or both need to be set");
+        }
+
+        // For mapping by URL
+        Iterable<UrlMapping> mappings = ((NginxController) driver.getEntity()).getUrlMappings();
+        Multimap<String, UrlMapping> mappingsByDomain = LinkedHashMultimap.create();
+        for (UrlMapping mapping : mappings) {
+            Collection<String> addrs = mapping.getAttribute(UrlMapping.TARGET_ADDRESSES);
+            if (addrs != null && addrs.size() > 0) {
+                mappingsByDomain.put(mapping.getDomain(), mapping);
+            }
+        }
+        Map<String, Object> substitutions = MutableMap.<String, Object>builder()
+                .putIfNotNull("ssl", ssl)
+                .put("urlMappings", mappings)
+                .put("domainMappings", mappingsByDomain)
+                .build();
+
+        // Get template contents and process
+        String contents = ResourceUtils.create(driver.getEntity()).getResourceAsString(templateUrl);
+        return TemplateProcessor.processTemplateContents(contents, driver, substitutions);
+    }
+
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMapping.java
----------------------------------------------------------------------
diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMapping.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMapping.java
new file mode 100644
index 0000000..fc2cedb
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMapping.java
@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import java.util.Collection;
+
+import org.apache.brooklyn.entity.proxy.AbstractController;
+import org.apache.brooklyn.entity.proxy.ProxySslConfig;
+
+import brooklyn.config.ConfigKey;
+import brooklyn.entity.Entity;
+import brooklyn.entity.annotation.Effector;
+import brooklyn.entity.basic.AbstractGroup;
+import brooklyn.entity.basic.ConfigKeys;
+import brooklyn.entity.basic.MethodEffector;
+import brooklyn.entity.proxying.ImplementedBy;
+import brooklyn.event.AttributeSensor;
+import brooklyn.event.basic.Sensors;
+import brooklyn.util.flags.SetFromFlag;
+
+import com.google.common.reflect.TypeToken;
+
+/**
+ * This is a group whose members will be made available to a load-balancer / URL forwarding service (such as nginx).
+ * Configuration requires a <b>domain</b> and some mechanism for finding members.
+ * The easiest way to find members is using a <b>target</b> whose children will be tracked,
+ * but alternative membership policies can also be used.
+ */
+@ImplementedBy(UrlMappingImpl.class)
+public interface UrlMapping extends AbstractGroup {
+
+    MethodEffector<Void> DISCARD = new MethodEffector<Void>(UrlMapping.class, "discard");
+
+    @SetFromFlag("label")
+    ConfigKey<String> LABEL = ConfigKeys.newStringConfigKey(
+            "urlmapping.label", "optional human-readable label to identify a server");
+
+    @SetFromFlag("domain")
+    ConfigKey<String> DOMAIN = ConfigKeys.newStringConfigKey(
+            "urlmapping.domain", "domain (hostname, e.g. www.foo.com) to present for this URL map rule; required.");
+
+    @SetFromFlag("path")
+    ConfigKey<String> PATH = ConfigKeys.newStringConfigKey(
+            "urlmapping.path", "URL path (pattern) for this URL map rule. Currently only supporting regex matches "+
+            "(if not supplied, will match all paths at the indicated domain)");
+
+    @SetFromFlag("ssl")
+    ConfigKey<ProxySslConfig> SSL_CONFIG = AbstractController.SSL_CONFIG;
+
+    @SetFromFlag("rewrites")
+    @SuppressWarnings("serial")
+    ConfigKey<Collection<UrlRewriteRule>> REWRITES = ConfigKeys.newConfigKey(new TypeToken<Collection<UrlRewriteRule>>() { },
+            "urlmapping.rewrites", "Set of URL rewrite rules to apply");
+
+    @SetFromFlag("target")
+    ConfigKey<Entity> TARGET_PARENT = ConfigKeys.newConfigKey(Entity.class,
+            "urlmapping.target.parent", "optional target entity whose children will be pointed at by this mapper");
+
+    @SuppressWarnings("serial")
+    AttributeSensor<Collection<String>> TARGET_ADDRESSES = Sensors.newSensor(new TypeToken<Collection<String>>() { },
+            "urlmapping.target.addresses", "set of addresses which should be forwarded to by this URL mapping");
+
+    String getUniqueLabel();
+
+    /** Adds a rewrite rule, must be called at config time. See {@link UrlRewriteRule} for more info. */
+    UrlMapping addRewrite(String from, String to);
+
+    /** Adds a rewrite rule, must be called at config time. See {@link UrlRewriteRule} for more info. */
+    UrlMapping addRewrite(UrlRewriteRule rule);
+
+    String getDomain();
+
+    String getPath();
+
+    Entity getTarget();
+
+    void setTarget(Entity target);
+
+    void recompute();
+
+    Collection<String> getTargetAddresses();
+
+    ProxySslConfig getSsl();
+
+    @Effector(description="Unmanages the url-mapping, so it is discarded and no longer applies")
+    void discard();
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMappingImpl.java
----------------------------------------------------------------------
diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMappingImpl.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMappingImpl.java
new file mode 100644
index 0000000..8252b05
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlMappingImpl.java
@@ -0,0 +1,223 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import static brooklyn.util.JavaGroovyEquivalents.groovyTruth;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.Set;
+
+import org.apache.brooklyn.entity.proxy.ProxySslConfig;
+import org.apache.brooklyn.entity.webapp.WebAppServiceConstants;
+import org.apache.brooklyn.management.SubscriptionHandle;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import brooklyn.entity.Entity;
+import brooklyn.entity.basic.AbstractGroupImpl;
+import brooklyn.entity.basic.Attributes;
+import brooklyn.entity.basic.Entities;
+import brooklyn.entity.basic.EntityPredicates;
+import brooklyn.entity.trait.Changeable;
+import brooklyn.entity.trait.Startable;
+import brooklyn.event.SensorEvent;
+import brooklyn.event.SensorEventListener;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+
+/**
+ * This is a group whose members will be made available to a load-balancer / URL forwarding service (such as nginx).
+ * <p>
+ * Configuration requires a <b>domain</b> and some mechanism for finding members.
+ * The easiest way to find members is using a <b>target</b> whose children will be tracked,
+ * but alternative membership policies can also be used.
+ */
+public class UrlMappingImpl extends AbstractGroupImpl implements UrlMapping {
+
+    private static final Logger log = LoggerFactory.getLogger(UrlMapping.class);
+
+    public UrlMappingImpl() {
+        super();
+    }
+
+    @Override
+    public String getUniqueLabel() {
+        String l = getConfig(LABEL);
+        if (groovyTruth(l)) return getId()+"-"+l;
+        else return getId();
+    }
+
+    /** adds a rewrite rule, must be called at config time.  see {@link UrlRewriteRule} for more info. */
+    @Override
+    public synchronized UrlMapping addRewrite(String from, String to) {
+        return addRewrite(new UrlRewriteRule(from, to));
+    }
+
+    /** adds a rewrite rule, must be called at config time.  see {@link UrlRewriteRule} for more info. */
+    @Override
+    public synchronized UrlMapping addRewrite(UrlRewriteRule rule) {
+        Collection<UrlRewriteRule> rewrites = getConfig(REWRITES);
+        if (rewrites==null) {
+            rewrites = new ArrayList<UrlRewriteRule>();
+        }
+        rewrites.add(rule);
+        setConfig(REWRITES, rewrites);
+        return this;
+    }
+
+    @Override
+    public String getDomain() {
+        return Preconditions.checkNotNull( getConfig(DOMAIN), "domain config argument required");
+    }
+
+    @Override
+    public String getPath() {
+        return getConfig(PATH);
+    }
+
+    @Override
+    public Entity getTarget() {
+        return getConfig(TARGET_PARENT);
+    }
+
+    @Override
+    public void setTarget(Entity target) {
+        setConfig(TARGET_PARENT, target);
+        recompute();
+    }
+
+    @Override
+    public void onManagementStarting() {
+        super.onManagementStarting();
+
+        if (getConfig(TARGET_PARENT) != null) {
+            recompute();
+            // following line could be more efficient (just modify the addresses set, not clearing it each time;
+            // but since addresses is lazy loaded not that big a deal)
+            // subscribe(this, Changeable.GROUP_SIZE, { resetAddresses(true) } as SensorEventListener);
+            // above not needed since our target tracking figures this out
+        }
+    }
+
+    /** defines how address string, ie  hostname:port, is constructed from a given entity.
+     * returns null if not possible.
+     * <p>
+     * the default is to look at HOSTNAME and HTTPS_PORT or HTTP_PORT attribute sensors (depending on SSL_CONFIG being set with targetIsSsl).
+     * <p>
+     * this method is suitable (intended) for overriding if needed.
+     */
+    protected String getAddressOfEntity(Entity s) {
+        String h = s.getAttribute(Attributes.HOSTNAME);
+
+        Integer p = null;
+        Set<String> protos = s.getAttribute(WebAppServiceConstants.ENABLED_PROTOCOLS);
+        ProxySslConfig sslConfig = getConfig(SSL_CONFIG);
+        if (sslConfig != null && sslConfig.getTargetIsSsl()) {
+            // use ssl
+            if (protos != null && hasProtocol(protos, "https")) {
+                // proto configured correctly
+            } else {
+                // proto not defined; use https anyway, but it might fail
+                log.warn("Misconfiguration for "+this+": ENABLED_PROTOCOLS='"+protos+"' for "+s+" but sslConfig="+sslConfig);
+            }
+            p = s.getAttribute(Attributes.HTTPS_PORT);
+            if (p == null)
+                log.warn("Misconfiguration for "+this+": sslConfig="+sslConfig+" but no HTTPS_PORT on "+s);
+        }
+        if (p == null) {
+            // default to http
+            p = s.getAttribute(Attributes.HTTP_PORT);
+        }
+
+        if (groovyTruth(h) && p != null) return h+":"+p;
+        log.error("Unable to construct hostname:port representation for "+s+"; skipping in "+this);
+        return null;
+    }
+
+    protected synchronized void recomputeAddresses() {
+        Set<String> resultM = Sets.newLinkedHashSet();
+        for (Entity s: getMembers()) {
+            String hp = getAddressOfEntity(s);
+            if (hp != null) resultM.add(hp);
+        }
+        Set<String> result = Collections.unmodifiableSet(resultM);
+        Collection<String> oldAddresses = getAttribute(TARGET_ADDRESSES);
+        if (oldAddresses == null || !result.equals(ImmutableSet.copyOf(oldAddresses))) {
+            setAttribute(TARGET_ADDRESSES, result);
+        }
+    }
+
+    public Collection<String> getTargetAddresses() {
+        return getAttribute(TARGET_ADDRESSES);
+    }
+
+    public ProxySslConfig getSsl() {
+        return getConfig(SSL_CONFIG);
+    }
+
+    // FIXME Do we really need this?!
+    protected SubscriptionHandle getSubscriptionHandle() {
+        return subscriptionHandle;
+    }
+
+    private SubscriptionHandle subscriptionHandle;
+    private SubscriptionHandle subscriptionHandle2;
+
+    @Override
+    public synchronized void recompute() {
+        if (subscriptionHandle != null) getSubscriptionContext().unsubscribe(subscriptionHandle);
+        if (subscriptionHandle2 != null) getSubscriptionContext().unsubscribe(subscriptionHandle2);
+
+        Entity t = getTarget();
+        if (t != null) {
+            subscriptionHandle = subscribeToChildren(t, Startable.SERVICE_UP, new SensorEventListener<Boolean>() {
+                @Override public void onEvent(SensorEvent<Boolean> event) {
+                    boolean changed = (event.getValue()) ? addMember(event.getSource()) : removeMember(event.getSource());
+                    if (changed) {
+                        recomputeAddresses();
+                    }
+                }});
+            subscriptionHandle2 = subscribe(t, Changeable.MEMBER_REMOVED, new SensorEventListener<Entity>() {
+                @Override public void onEvent(SensorEvent<Entity> event) {
+                    removeMember(event.getValue());
+                    // recompute, irrespective of change, because framework may have already invoked the removeMember call
+                    recomputeAddresses();
+                }});
+            setMembers(t.getChildren(), EntityPredicates.attributeEqualTo(Startable.SERVICE_UP, true));
+        }
+
+        recomputeAddresses();
+    }
+
+    @Override
+    public void discard() {
+        Entities.unmanage(this);
+    }
+
+    private boolean hasProtocol(Collection<String> protocols, String desired) {
+        for (String contender : protocols) {
+            if ("https".equals(contender.toLowerCase())) return true;
+        }
+        return false;
+    }
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlRewriteRule.java
----------------------------------------------------------------------
diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlRewriteRule.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlRewriteRule.java
new file mode 100644
index 0000000..687fb63
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/proxy/nginx/UrlRewriteRule.java
@@ -0,0 +1,74 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.proxy.nginx;
+
+import java.io.Serializable;
+
+/** records a rewrite rule for use in URL rewriting such as by nginx;
+ * from and to are expected to be usual regex replacement strings,
+ * with the convention here (for portability) that:
+ * <li>
+ * <it> from should match the entire path (internally is wrapped with ^ and $ for nginx);
+ * <it> to can refer to $1, $2 from the groups in from
+ * </li>
+ * so eg use from = (.*)A(.*)  and to = $1B$2 to change all occurrences of A to B
+ */
+public class UrlRewriteRule implements Serializable {
+    
+    private static final long serialVersionUID = -8457441487467968553L;
+    
+    String from, to;
+    boolean isBreak;
+    
+    /* there is also a flag "last" possible on nginx which might be useful,
+     * but i don't know how portable that is --
+     * we'll know e.g. when we support HA Proxy and others.
+     * presumably everything has at least one "break-after-this-rewrite" mode
+     * so i think we're safe having one in here.
+     */
+
+    public UrlRewriteRule() {}
+    public UrlRewriteRule(String from, String to) {
+        this.from = from;
+        this.to = to;
+    }
+    
+    public String getFrom() {
+        return from;
+    }
+    public void setFrom(String from) {
+        this.from = from;
+    }
+    public String getTo() {
+        return to;
+    }
+    public void setTo(String to) {
+        this.to = to;
+    }
+        
+    public boolean isBreak() {
+        return isBreak;
+    }
+    public void setBreak(boolean isBreak) {
+        this.isBreak = isBreak;
+    }
+
+    public UrlRewriteRule setBreak() { setBreak(true); return this; }
+    
+}

http://git-wip-us.apache.org/repos/asf/incubator-brooklyn/blob/77dff880/software/webapp/src/main/java/org/apache/brooklyn/entity/webapp/ControlledDynamicWebAppCluster.java
----------------------------------------------------------------------
diff --git a/software/webapp/src/main/java/org/apache/brooklyn/entity/webapp/ControlledDynamicWebAppCluster.java b/software/webapp/src/main/java/org/apache/brooklyn/entity/webapp/ControlledDynamicWebAppCluster.java
new file mode 100644
index 0000000..18d2eb8
--- /dev/null
+++ b/software/webapp/src/main/java/org/apache/brooklyn/entity/webapp/ControlledDynamicWebAppCluster.java
@@ -0,0 +1,114 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.brooklyn.entity.webapp;
+
+import org.apache.brooklyn.catalog.Catalog;
+import org.apache.brooklyn.entity.proxy.LoadBalancer;
+
+import brooklyn.config.ConfigKey;
+import brooklyn.entity.Entity;
+import brooklyn.entity.Group;
+import brooklyn.entity.basic.Attributes;
+import brooklyn.entity.basic.ConfigKeys;
+import brooklyn.entity.basic.ConfigurableEntityFactory;
+import brooklyn.entity.basic.DynamicGroup;
+import brooklyn.entity.basic.Lifecycle;
+import brooklyn.entity.group.Cluster;
+import brooklyn.entity.group.DynamicCluster;
+import brooklyn.entity.proxying.EntitySpec;
+import brooklyn.entity.proxying.ImplementedBy;
+import brooklyn.entity.trait.MemberReplaceable;
+import brooklyn.entity.trait.Resizable;
+import brooklyn.entity.trait.Startable;
+import brooklyn.event.AttributeSensor;
+import brooklyn.event.basic.BasicAttributeSensor;
+import brooklyn.event.basic.BasicAttributeSensorAndConfigKey;
+import brooklyn.util.flags.SetFromFlag;
+
+/**
+ * This entity contains the sub-groups and entities that go in to a single location (e.g. datacenter)
+ * to provide web-app cluster functionality, viz load-balancer (controller) and webapp software processes.
+ * <p>
+ * You can customise the web server by customising the memberSpec.
+ * <p>
+ * The children of this entity are:
+ * <ul>
+ * <li>a {@link brooklyn.entity.group.DynamicCluster} of {@link WebAppService}s (defaults to JBoss7Server)
+ * <li>a cluster controller (defaulting to Nginx if none supplied)
+ * </ul>
+ * 
+ * This entity is also a group whose members mirror those of the child DynamicCluster (so do not include the load balancer).
+ * This is convenient for associating policies such as ServiceReplacer with this entity, rather 
+ * than with the child {@link brooklyn.entity.group.DynamicCluster}. However, note that changing this entity's
+ * members has no effect on the members of the underlying DynamicCluster - treat this as a read-only view.
+ */
+@Catalog(name="Controlled Dynamic Web-app Cluster", description="A cluster of load-balanced web-apps, which can be dynamically re-sized")
+@ImplementedBy(ControlledDynamicWebAppClusterImpl.class)
+public interface ControlledDynamicWebAppCluster extends DynamicGroup, Entity, Startable, Resizable, MemberReplaceable,
+        Group, ElasticJavaWebAppService, JavaWebAppService.CanDeployAndUndeploy, JavaWebAppService.CanRedeployAll {
+    
+    @SetFromFlag("initialSize")
+    public static ConfigKey<Integer> INITIAL_SIZE = ConfigKeys.newConfigKeyWithDefault(Cluster.INITIAL_SIZE, 1);
+
+    @SetFromFlag("controller")
+    public static BasicAttributeSensorAndConfigKey<LoadBalancer> CONTROLLER = new BasicAttributeSensorAndConfigKey<LoadBalancer>(
+        LoadBalancer.class, "controlleddynamicwebappcluster.controller", "Controller for the cluster; if null a default will created (using controllerSpec)");
+
+    @SetFromFlag("controlledGroup")
+    public static BasicAttributeSensorAndConfigKey<Group> CONTROLLED_GROUP = new BasicAttributeSensorAndConfigKey<Group>(
+        Group.class, "controlleddynamicwebappcluster.controlledgroup", "The group of web servers that the controller should point at; if null, will use the CLUSTER");
+
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @SetFromFlag("controllerSpec")
+    public static BasicAttributeSensorAndConfigKey<EntitySpec<? extends LoadBalancer>> CONTROLLER_SPEC = new BasicAttributeSensorAndConfigKey(
+            EntitySpec.class, "controlleddynamicwebappcluster.controllerSpec", "Spec for creating the controller (if one not supplied explicitly); if null an NGINX instance will be created");
+
+    @SuppressWarnings({ "unchecked", "rawtypes", "deprecation" })
+    /** factory (or closure) to create the web server, given flags */
+    @SetFromFlag("factory")
+    public static BasicAttributeSensorAndConfigKey<ConfigurableEntityFactory<? extends WebAppService>> FACTORY = new BasicAttributeSensorAndConfigKey(
+            ConfigurableEntityFactory.class, DynamicCluster.FACTORY.getName(), "factory (or closure) to create the web server");
+
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    /** Spec for web server entiites to be created */
+    @SetFromFlag("memberSpec")
+    public static BasicAttributeSensorAndConfigKey<EntitySpec<? extends WebAppService>> MEMBER_SPEC = new BasicAttributeSensorAndConfigKey(
+            EntitySpec.class, DynamicCluster.MEMBER_SPEC.getName(), "Spec for web server entiites to be created");
+
+    @SuppressWarnings({ "unchecked", "rawtypes" })
+    @SetFromFlag("webClusterSpec")
+    public static BasicAttributeSensorAndConfigKey<EntitySpec<? extends DynamicWebAppCluster>> WEB_CLUSTER_SPEC = new BasicAttributeSensorAndConfigKey(
+            EntitySpec.class, "controlleddynamicwebappcluster.webClusterSpec", "Spec for creating the cluster; if null a DynamicWebAppCluster will be created");
+
+    public static AttributeSensor<DynamicWebAppCluster> CLUSTER = new BasicAttributeSensor<DynamicWebAppCluster>(
+            DynamicWebAppCluster.class, "controlleddynamicwebappcluster.cluster", "Underlying web-app cluster");
+
+    public static final AttributeSensor<String> HOSTNAME = Attributes.HOSTNAME;
+
+    public static final AttributeSensor<Lifecycle> SERVICE_STATE_ACTUAL = Attributes.SERVICE_STATE_ACTUAL;
+
+    
+    public LoadBalancer getController();
+    
+    public ConfigurableEntityFactory<WebAppService> getFactory();
+    
+    public DynamicWebAppCluster getCluster();
+    
+    public Group getControlledGroup();
+}